chapter 08 discrete state process control

8/18/2019 Chapter 08 Discrete State Process Control

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Industrial Instruments 2Industrial Instruments 2Chapter 8Chapter 8

Discrete-State Process ControlDiscrete-State Process ControlDr. Bassam KahhalehDr. Bassam Kahhaleh

Princess Sumaya Uni.Princess Sumaya Uni.

!lectronic !n"ineerin" Dept.!lectronic !n"ineerin" Dept.


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Princess Sumaya UniersityPrincess Sumaya Uniersity 3442 - Industrial Instruments 23442 - Industrial Instruments 2 22 # 32# 32

8$ Discrete-State Process Control8$ Discrete-State Process Control

DefinitionsDefinitions%he%he discrete statediscrete state o& the process at anyo& the process at any

moment is the set o& all input and outputmoment is the set o& all input and output

alues.alues. 'n 'n event event in the system is de&ined (y ain the system is de&ined (y aparticular state o& the system) i.e. particularparticular state o& the system) i.e. particularalues o& inputs and outputs.alues o& inputs and outputs.

' ' discrete-state process control discrete-state process control is ais aparticularparticular sequence of sequence of eventsevents throu"h *hichthrou"h *hich

the processthe process accomplishesaccomplishes some o(+ectiesome o(+ectie


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ExampleExam

ple

,rost-&ree re&ri"erator#&reeer ,rost-&ree re&ri"erator#&reeer

Discrete-state I#PDiscrete-state I#P

Door open#closedDoor open#closed Cooler temp. hi"h#lo*Cooler temp. hi"h#lo* ,reeer temp. hi"h#lo*,reeer temp. hi"h#lo* Po*er s*itch on#o&& Po*er s*itch on#o&& ,rost detector on#o&& ,rost detector on#o&& ,rost eliminator timer out#not out,rost eliminator timer out#not out


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ExampleExam

ple

,rost-&ree re&ri"erator#&reeer ,rost-&ree re&ri"erator#&reeer

Discrete-state #PDiscrete-state #P

/i"ht on#o&& /i"ht on#o&& Compressor on#o&& Compressor on#o&& %imer on#o&& %imer on#o&& 0eater on#o&& 0eater on#o&& Ba&&le open#closedBa&&le open#closed


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Discrete-State VariablesDiscrete-State Variables Continuous ControlContinuous Control


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Discrete ControlDiscrete Control


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Princess Sumaya UniersityPrincess Sumaya Uniersity 3442 - Industrial Instruments 23442 - Industrial Instruments 2 # 32# 32



Discrete ControlDiscrete Control

CompositeCompositeDiscrete#ContinuousDiscrete#Continuous

ControlControl


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Process SpecificationsProcess Specifications Process (+ectiesProcess (+ecties

Process 0ard*areProcess 0ard*are

Input DeicesInput Deices /imit S*itches/imit S*itches

ComparatorsComparators

Push ButtonsPush Buttons

utput Deicesutput Deices

/i"hts/i"hts

5otors5otors

SolenoidsSolenoids


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Event Sequence DescriptionEvent Sequence Description 7arratie Statements7arratie Statements

,lo*charts,lo*charts

Binary-StateBinary-State

99:

: #

9 # 9

#

: # 9


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Event Sequence DescriptionEvent Sequence DescriptionFlowchart ExampleFlowchart Example


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Event Sequence DescriptionEvent Sequence DescriptionFlowchart ExampleFlowchart Example


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Event Sequence DescriptionEvent Sequence DescriptionBinary-State ExampleBinary-State Example

9.9. ,ill the tan; to leel ',ill the tan; to leel '

&rom ale '.&rom ale '.

2.2. ,ill the tan; to leel B,ill the tan; to leel B

&rom ale B.&rom ale B.

3.3. Start the timer) heat) andStart the timer) heat) and

stir &or 1 minutes.stir &or 1 minutes.

4.4. pen output ale Cpen output ale C

until the empty s*itchuntil the empty s*itch

en"a"es.en"a"es.


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I/P VariablesI/P Variables

/'/'

/B/B

/!/!

%U%U

O/P VariablesO/P Variables


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State$ /' /B /! %U


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Relay Controllers & Laer Dia!ra"sRelay Controllers & Laer Dia!ra"s Control =elays >=elay Se?uencer@Control =elays >=elay Se?uencer@


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Relay Controllers & Laer Dia!ra"sRelay Controllers & Laer Dia!ra"s /adder Dia"ram/adder Dia"ram


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Relay Controllers & Laer Dia!ra"sRelay Controllers & Laer Dia!ra"sLadder Diagram ExampleLadder Diagram Example


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9. Ahen the S%'=% (utton is pushed)

the plat&orm is drien to the do*n

position.

2. Ahen the S%P (utton is pushed)

the plat&orm is halted at *hateer

position it occupies at that time.

3. Ahen the UP (utton is pushed) the

plat&orm) i& it is not in do*n*ardmotion) is drien to the up position.

4. Ahen the DA7 (utton is pushed)

the plat&orm) i& it is not in up*ard

motion) is drien to the do*n

position.


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Start

Stop


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S%'=%

S%P

Po*er


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S%'=%

S%P

Po*er

5otor


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Po*er Do*n

S%P

S%'=%

5otor

5otor UP


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CR

CR


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#ar$ire Pro!ra""in!#ar$ire Pro!ra""in! =elay Se?uencers=elay Se?uencers

Pro!ra""able Lo!ic Controllers %PLCsPro!ra""able Lo!ic Controllers %PLCs

Processor Processor Input 5odulesInput 5odules

utput 5odulesutput 5odules


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Pro!ra""able Lo!ic Controllers %PLCsPro!ra""able Lo!ic Controllers %PLCs Input 5oduleInput 5odule


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Pro!ra""able Lo!ic Controllers %PLCsPro!ra""able Lo!ic Controllers %PLCs utput 5oduleutput 5odule


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Pro!ra""able Lo!ic Controllers %PLCsPro!ra""able Lo!ic Controllers %PLCs /o"ic Pro"rammin"/o"ic Pro"rammin"

Usin" a 7C s*itch to turn o&& a

li"ht *ith relay lo"ic and

*ith P/C pro"rammin"$

a@ %he (utton turns the li"ht

,,.

(@ Aith relay lo"ic the (utton

turns the li"ht 7.c@ Aith a P/C pro"ram the

(utton turns the li"ht 7


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Pro!ra""able Lo!ic Controllers %PLCsPro!ra""able Lo!ic Controllers %PLCs /o"ic Pro"rammin"/o"ic Pro"rammin"

7 s*itches are

considered I!"#I$E

*hen they are read asopen circuit) and

!"#I$E *hen they are

read as closed circuit.

In the ladder dia"ram) 9

must (e !"#I$E *hile

3 must (e I!"#I$E

to turn 8 7.


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chapter 08 discrete state process control

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